1. Field of the Invention
This invention relates to an apparatus for testing a tube for its strength to resist internal pressure. Though various tubes can be tested in the apparatus according to the present invention, a .beta.-aluminum tube, which may be used as a solid electrolyte in a sodium-sulfur cell, is particularly suited to be tested in the apparatus according to the present invention.
2. Description of the Prior Art
To test the strength of a .beta.-aluminum tube to resist internal pressure, one method has been known in which the open end of a tube is tightly contacted to a head that provides pressurized water, and then pressurized water is poured into the tube. A tube that does not stand a specific pressure is destroyed. This method, however, has a disadvantage that it takes considerable time and cost to dry the tubes that pass the test.
To overcome this disadvantage, an apparatus for testing a tube for its strength by expanding an elastomer up to a specific pressure inside a tube to be tested, has been disclosed by the present applicants in Japanese Utility Model Application Laid Open No. 1-97241 (1989). In this apparatus it is necessary to cover an elastomer by a tube one after one by hand, and it is highly inconvenient to test numerous tubes continuously. Moreover, when an elastomer expands inside a tube to be tested in this apparatus, sometimes the tube is not pushed evenly but to one direction, and an area close to the open end of the tube gets contacted with a metallic part outside the tube in the apparatus to result to scratches and damages in the area of the tube.